Method for texturing thermoplastic yarn and apparatus



Sept. 7, 1965 METHOD FOR TEXTURING Filed Aug. 21, 1961 B. H. FOSTER ETAL THERMOPLASTIC YARN AND APPARATUS '.5 Sheets-Sheet 1 :gl a

ATTORNEY METHOD FOR TEXTURING THERMOPLASTIC YARN AND APPARATUS 5 Sheets-Sheet 2 Filed Aug. 2l, 1961 ATTORNEY Sept. 7, 1965 B. H. FOSTER ETAL METHOD FOR TEXTURING THERMOPLASTIC YARN AND APPARATUS 5 Sheets-Sheet 3 Filed Aug. 2l, 1961 United States Patent Oiiice 3,204,396 Patented Sept. 7, 1965 3,204,396 METHOD FOR TEXTURHNG THERMOPLASTIC YARN AND APPARATUS Boutwell H. Foster, Maplewood, and Richard H. Hugger, Ridgewood, NJ., assignors to United States Rubber Company,`New York, NSY., a 'corporation of New Jersey Filed Aug. 21, 1961, Ser. No. 132,823 18 Claims. (Cl. 57-34) This invention relates to textile yarn Itexturin-g method and apparatus of the false twist type and to a novel false twisting device.

Continuous multi-lilament thermoplastic textile yarns, such as nylon, polyester (eg. that sold under the trademark Dacron) polypropylene, etc. are textured by highly twisting the yarns, heat-relaxing them in the twisted condition, and thereafter removing all or a major part of the initial twist. Commonly the resultant yarn is used in a ply yarn construction with another yarn that had been twisted in the opposite direction when it was heatrelaxed.

When the twist is inserted by a'false twister, the process generally is a continuous one in which the yarn first passes through the heating area before reaching the false twister; the false or temporary twist runs i.e. extends, back `from the twister into the heating area; the twist is removed as the yarn passes the twister and the un-twisted yarn is collected.

In this invention a circulating air oven is used to heatrelax the twisted yarn in combination with an improved air false twisting nozzle.

An eiiicient air false twist nozzle is disclosed and claimed in Foster et al. United States Patent No. 2,515,299. The improved false twister employed in the present apparatus has a passage Ifor the yarn including a chamber, desira'bly conical in shape, in which whirling fluid, such as air, acts on the yarn to twist it. A nipple, preferably frusto-c'onically shaped, .points into that chamber opposite the direction of yarn advanced, and has a bore centrally therethrough for the yarn to pass through. The air is introduced in jets opposite this nipple. Twisting speeds of over one million revolutions per minute 'had been achieved with the improved nozzle without fouling the nozzle.

A circulating air oven is employed in this apparatus to heat-relax the yarn. With this device yarn processing speeds of 800 to 1200 feet per minute have been achieved in which all the fibers in the yarn were well set in the oven.

It is believed the circulating 'air oven contributes to the successful operation of the apparatus for a number of reasons. In this invention the yarn travels a straight, or nearly straight, line path through the oven and nozzle. When a circulating Ihot -air oven is used the yarn need not be restricted during the period in which it is twisted. This permits a higher proportion of the .twist imparted to -t-he yarn to enter the heating zone. Another advantage of this is that by allowing ballooning in the yarn, maximum heat transfer is assured. When heat is being transferred between a fluid -and a solid object, there is invariably a boundary layer of stagnant uid surrounding the solid object which insulates the solid object and grea-tly reduces t-he coetlicient of heat transfer. The rapid whirling of the ballooned yarn which occurs in this invention in the oven reduces this insulating layer, and thereby increases the eiciency of heat transfer. Additionally the design of the circulating air oven of the invention provides uniform temperature distribution and control throughout the length of each heating oven. Finally, by returning and reuti-lizing spent hot air, maximum thermal efficiency for the unit is approached.

The air nozzle 4twister employed in this invention permits operation vat very high twisting speeds, which in turn permits high linear y-arn speeds through the apparatus for -any desired degree of twisting. Further, S and Z twisting stations can readily 'be paired side by side without complex mechanisms to change the rotation of mechanical elements, `and this in turn permits plying at the textured yarn take-up station of oppositely twisted yarn into a balanced construction. The air type false twister also achieves rapid cooling of the heat -set yarn before untwisting -because the incoming yarn is subjected to the refrigerating effect of the compressed air that is escaping from the nozzle.

Heated air is introduced to .the circu-lating air oven symmetrically with respect to the yarn passage therethrough and at low air velocity. The oven is constructed to introduce the air in the downstream area, .to pass it counter to the yarn travel and to remove it at the upstream area.

For a better understanding of the nature of this invention, reference should 'be had to the follow-ing detailed description of a specic embodiment thereof when read in conjunction with the accompanying drawings, where- FIG. 1 is a schematic perspective view partly broken away of the false 4twist nozzle;

FIG. 2 is an end elevation of the texturing apparatus;

FIG. 3 is a partly schematic side elevation of the texturing yapparatus of lFIG. 2 with parts broken away looking at the left side of FIG. 2;

FIG. 4 is a view similar to FIG. 3 illustrating the hot air sup-ply employed in the apparatus, and

FIG. 5 is a sectional View along the line 5-5 of FIG. 3.

Referring iirst to FIG. 2, the travel of the yarn 10 from pirn '11 is through pigtails `12, 13; then through button tensioner 14 and guide 15 to .the nip 0f steel roll 16 and rubber covered lpresser roll 17. Steel roll 16 is driven in the direction indicated by .the arrow, and if desired it may, in cooperation with a small diameter roll spaced therefrom form one of `a pair of Godet rolls t-o advance the yarn. |In the apparatus illustrated in the drawing, the yarn passes partially around roll 16 .to pigtail 18 to be directed thence upwardly on a substantially straight line path to idle rod 19. Between pigtail 18 and rod 19, the yarn rst passes through the circulating hot air oven 20 and Ithen through air false twister 21. lFrom rod 19 the yarn comes under control of a traverse device indicated only generally at 22 in FIG. 2 and finally is wound on package 23 that rests on and is frictionally driven by rotating steel roll 24.

Additional textu-ring stations are provided on either side of the described station as Well as on rthe opposite side of the frame in the manner customary iin textile yarn handlin-g machines.

The false twist device 21 is tapped into holder 25 and communicates through la control needle valve and through a T connection for a pressure gauge with manifold 26 supplied with pressurized air through hose 27 :from an lair source such -as a conventional compressor (not shown). The sever-al false twisting devices on that side of the machine, whether S or Z, yare similarly connected to manifold 26.

The air if-alse twister is shown in detail in `FIG. 1, and can be seen to comprise tube 28 communicating between holder f2.5 and cylindrical jacket 29. Jacket l29 together with :a two piece :insert complete the air false twist device or nozzle 21. The tirst insert inclu-des a cylindrical section 30, an integral reduced diameter cylindrical nipple base 311 between the section `30 and the bottom of the truste-conical nipple 3.2 `that points inwardly ofthe nozzle. A cylindrical portion 33 of reduced diameter is integral with the section 30 at the outer face thereof opposite the nipple 32. This iirst insert has an .axial passage therethrough extending fr-om the truncated peak of nipple 32 through ,this nipple. This passage extends coniCa'lly part way through section 30 to an enlarged diameter cylindrical hole that opens to the outside of the nozzle.

The second insert includes a cylindrical section 34 to which is integrally attached a cylindrical bo-re body 35 of reduced diameter extending from section 34 at its inward face, and :a second .cylindrical section 3,6 of reduced diameter integral therewith and extending outwardly of the nozzle. This second insert similarly has yan :axial opening therethrough which begins with la cylindrical passage that exten-ds from the outer face of section 36 inwardly :a short distance and terminates at Ithe apex side of :a frustoconical hole that extends through cylindrical section 34 and terminates in 'a cylindrical hole of a diameter such that its inner walls will tightly dit over nipple base 31.

The two inserts are of such dimension that cylindrical sections 30, 34 t within and close cylindrical jacket 29 and dene between their inner faces :and the outer cylindrical surface of cylindrical bore body 35 -a plenum charnber communicating with tube 28.V In the embodiment shown in the drawing bore body 35, nipple 32 and nipple base 31 are so proportioned that when the inner lEa-ce of bore body 35 abuts the inner face of cylindrical section 30, the apex end of nipple 32 extends to the base of the frusto-conical section 34. Consequently in that embodiment, nipple 32 is disposed within a cylindrical opening and extends substantially completely through that par-t of the cylindrical chamber that remains open when the device isV assembled.

Bore body 35 has four bores, one of which is shown :at 37, eac-h spaced 90 from its neighbors. The 4bores 37 extend generally radially through bore body 35 and communicate between the plenum surrounding bore .body 35 and the cylindrical hole within bore body 35. The bores I37 are arranged with their inner ends tangent to the surface -dening the outer wall of the cylindrical hole within bore body 35 and are disposed longitudinally of the nozzle in :a position opposite the conical surface ot nipple 32 intermediate the end-s of this nipple.

'Pressurized air admitted to tube 28 will pass to the plenum cham-ber of the air false twister, from that cham- -ber through bores 37 to .be jetted into and -whirled 'around in the cylindrical hole within bore body 35, to pass into the frusto-conical passage in the bottom insert shown in the drawing to escape through the external ent-rance passage in the bottom insert .and through the bore extending through nipple 32. Preferably the pressurized -air is substantially below the heat :setting temperature of the yarn being textured, and conveniently it can be at substantially room temperature. The yarn passes through the device lfrom bottom t-o top as seen in FIG. 1 and it is twisted on the bott-om side of, ie. beneath, the nozzle. The direction of twist, Whether S or Z, depends upon the direction of entry of bores 37 which in turn determine whether the air is swirling clockwise or counter-clockwise in the passage through the air jet twister 21.

The 4following specific example of :an air false twister will further illustrate this invention. The cylindrical section 30 is W32 long and .375 in diameter; cylindrical portion 33 is 1/16 long Iand 1A" in external diameter; nipple base 31 is 5%4 long and .109 in diameter; nipple 32 is 5%;4 long, it has a cone :angle of 45 and an external diameter at the apex end of the frustum of 1%4. The bore which extends through nipple 32, nipple base 31 and partly through section 30 is .020 in `diameter and about .133" long. The large bore through cylindrical portion 33 is Ms in diameter and V.148 long. Cylindrical portion 34 has the same external dimensions 'as cylindrical section 30; cylindrical section 36 is 1A" 1in diameter and %2 long, and bore 'body 35 has an external diameter of .20" land is s" long. The cylindrical opening in the bottoni face of cylindrical section 36 is .052" in diam-y eter and extends inwardly rfrom that face 1/322 The cone angle of hte Vfausto-conical passage through t-he bottom insert is 131/2 the cylindrical chamber within bore body 35 is .109" .in diameter and extends inwardly i.e. downwardly, from the t-op face of bore body 35 a distance of 3/32". The bores 37 through bore body 3S were drilled on centers spaced 1/16 down from the upper end face of .bore body 35, 4and bores 37 have a diameter .018. There were four such'bores 37 spaced 90 from each other. The Iseveral central openings through the two inserts have a common axis which is the axis of the cylindrical jacket 29.

The circulating hot air oven 20 is illustrated lin detail in 'F-IGS. 2 through 5 inclusive. Referring lirst to FIG. 4, a blower 38 driven by .a motor 39 circulates the air. Hot air duct 40 connects the outlet of blower 38 and extends along the length of the frame to supply several individual hot air boxes which will be described hereinafter that in turn lsupply the air to the ovens for the several spindles carried on either side of the frame. A damper 41 extends along the length of duct 40 opposite the individual hot air boxes and is pivoted :at its left end so that it can be moved either up Ior down to regulate air :Flow through duct- 40. The path of air is from blower 38 .through duct 40 from the lett-hand end to the right-hand end as seen in FIG. 4 above damper 41, thence below damper 41 from the right-hand end of duct 40 to the left-hand end :as seen in FIG. 4. The lateral walls ot duct 40 cont-ain a nu-rnber of circular holes 4.2 which communicate between duc-t 40 and a blend-ing chamber 43 (see IFIG. 2) which extends a-long the length of the trame and communicates between duct 40 'and the hot air boxes next to be described.

As appears from FIGS. 3 and 5 there are disposed along the length of the frame a number of hot air boxes 44 each with a slot 45 in its upper end that opens into the blending chamber 43. Symmetrically Ispaced from the yarn path, two hot air boxes 44 are provided for each yarn with one on each side of each yarn path. All but the hot air boxes in the terminal positions on the frame permit escape of hot air in the manner to be described hereinafter from both lateral sides of the box so as to lprovide air to the yarn in the oven on both sides of the Thus individual ovens are provided for each yarn with the path of the yarn lying approximately in the center of' the cross-section of the oven. The ovens are rectangular in cross-section with a hot air box 44 dening its two lateral sides, a back closing plate 70 forming its back and its face being formed by"'insulatiou 46 that substantially closes its face.

As appears best in FIGS. 3 and 5, insulation 46 has slots 71 extending the length of the oven and terminating at each end with an interrupted generally cylindrical eyelet 72 so the yarn can be inserted easily in the oven or removed therefrom by the simple expedient of moving the entire yarn through a slot 71 in insulation 46 and into or out of the oven without rethreading the device.

An elongated slot 48 is provided at the bottom section of each oven through the back plate of the oven. Slot 48 communicates with duct 49 which in turn communicates with return manifold 50 connected to the inlet of blower 38. A slide 51 is provided to close slot 48, and this slide may be moved vertically to open or close slot 48 to a greater or less extent, thus permitting control of hot air ilow to each yarn end. Electrical resistance heaters heat the air before it enters blower 38 to be recirculated,

The right-hand side (as seen in FIG. 4) of the floor of duct 40 is a slide 73 which may be removed partially or completely as desired. Since the bottom of duct 40 is also the top of return duct 50, opening this slide will bypass some of the heated air at this point to the return duct. In one embodiment this slidable section of the inlet duct bottom is 8 inches long, and it may beI regulated to a fully open position, a fully closed position, and any setting in between.

The side plates 74 of hot air boxes 44 are formed of perforated metal. The size and area of the openings through these side plates as well as the air pressure within the boxes 44 are important factors in the eicient heating of yarn in the oven. lf the hot air is ejected too rapidly into the oven from the boxes, turbulent air ow and thus lower yarn quality will result. It has been found that with two side plates for each oven as illlustrated, perfolrated metal with 1&2 diameter holes through it, 1A; of the total area of the plate being occupied by the holes, and a pressure within the boxes 44 in the range of 0.20 to 0.65 inch of water, efiicient heating is obtained.

When two 'side plates are employed, the pressure should be within that range, the holes should have a diameter in the range of l@ inch to 1A inch, and the percent of open area in the plates should be from 5% to 20%.

As further illustrating the invention, the following specific example is given. The individual oven height is approximately 30 inches. Its cross-section is two inches deep (space between plate 70 and face insulation 46) by 31/2 inches wide (space between boxes 44). The -inlet slot 45 extends through approximately 1/3 the length of box 44 from top to bottom (i.e. about 10"), and the outlet slot 48 extends through approximately 1A the length of the oven from top to bottom (i.e. about Both sets of slots are each about 2 inches wide.

Using the specific nozzle described above with an air pressure of 62 pounds per square inch, twisting speeds of 1,200,000 rpm. can be obtained. At these twisting speeds and at yarn advance speeds of 800 to 900 feet per minute, an air temperature in the oven of from 500 to 600 degrees F. produced by twenty-four 1000 watt resistant heaters achieves a good yarn.

If desired, an air diffuser can be applied to the inlet end of the nozzle. Such a diffuser would necessitate increasing the air pressure in the nozzle to achieve the same twisting speed, but it would permit closer control of the air temperature in the heating oven by eliminating from the oven the blast leaving the nozzle.

The following specific examples of yarns textured in the apparatus of this invention will further illustrate the invention.

Example 1 2 3 4 5 Yarn Type (70 denier continuous filament nylon) 288 288 288 200 200 No. Filaments 34 34 34 34 34 Initial Twist Z M Z 0 0 Feed Speed (f.p.m.) 850 850 850 860 860 Take-up Speed (fpm.) 797 '797 797 785 782 Wind-up Speed f.p.m.) 795 795 795 785 775 Process Twist Z Z Z S and S ang Control Temp. Setting F.) 470 470 470 520 500 Air Pressure (at Nozzle) 80 80 80 70 74 Turns Per Minute.. 1. 06x10 1. 05 10 1. 05 106 Percent shrinkage 1 49 45. 5 46. 5 19. 3 30. G Percent Strength Reduction Negl. 11 5. 2 10. 7 18. 8

diffuser diffuser diffuser present present present l Determined by procedure outlined in Universal Winding Company test procedure titled "How to Test Superloft and Flufion Stretch Yarns," dated April 1959.

Using the air nozzle of this invention, independent control of twisting speeds at each twisting station is easily accomplished. A valve in the air supply line can be adjusted to vary the air pressure at the twisting station. Conveniently a pressure gauge is connected to the T as a visual indication of the pressure effective in the twisting nozzle. The use of such adjustable pressure devices is especially convenient where the raw material contains a slight pretwist in one direction that will require that the twisting station which twists a yarn in the opposite direction run slightly faster than the twisting station which merely adds to the pretwist when yarns for balanced constructions are desired. At other times it may be desired to impart unbalanced twists to the yarns, and the adjustable air source is convenient for this purpose.

Having thus described our invention, what we claim and desire to protect by Letters Patent is:

1. A twister comprising a wall defining an elongated chamber, one part of which is cylindrical in shape and another part of which is conical in shape with the base of such conically shaped part being coincident with and of the same diameter as said cylindrical shaped part and the axes of both said parts being aligned, a nipple projecting into the cylindrical part of said chamber along the axis thereof, said twister having an axial yarn inlet opening into said chamber at the apex end of said conically shaped part and an axial opening in said nipple for exit of yarn therefrom, and means in the wall of said chamber disposed intermediate the ends of said nipple for introducing fluid jets into the cylindrical part of said chamber.

2. A twister in accordance with claim 1 in which said nipple has a conically shaped end pointing toward said conically shaped part of said chamber and in which said nipple extends substantially completely through said cylindrical shaped part of said chamber.

3. A twister in accordance with claim 2 in which said inlet opening is larger than said exit opening.

4. Apparatus for texturing thermoplastic yarn comprising a forced hot air oven to soften said yarn while said yarn is twisted, a iiuid twisting nozzle adapted to twist yarn passing therethrough, said iiuid twisting nozzle including walls defining a vacant twisting chamber, means for whirling said iiuid in contact with the yarn and about the axis of said chamber and to move the fluid axially into and through said chamber in a direction counter to the direction of yarn advanced therethrough, and means for passing thermoplastic yarn to be textured on a substantially straight line path first through said forced hot air oven and then through said twisting nozzle, said iiuid twisting nozzle and means for passing yarn being constructed and arranged to balloon the yarn in the circulating hot air oven.

5. Apparatus in accordance with claimI 4 in which said fluid twisting nozzle includes a wall defining an elongated chamber, one part of which is cylindrical in shape and another part of which is conical in shape with the base of such conically shaped part being coincident with and of the same diameter as said cylindrical shaped part and the axes of both said parts being aligned, a nipple projecting into the cylindrical part of said chamber along the axis thereof, said twister having an axial yarn inlet opening into said chamber at the apex end of said conically shaped part and an axial opening in said nipple for exit of yarn therefrom, and means in the wall of said chamber disposed intermediate the ends of said nipple for introducing fluid jets into the cylindrical part of said chamber.

6. Apparatus in accordance with claim 5 in which said nipple has a conically shaped end pointing toward said conically shaped part of said chamber and in which said nipple extends substantially completely through said cylindrical shaped part of said chamber.

7. Apparatus in accordance with claim 6 in which said inlet opening is larger than said exit opening.

8. A method for texturing yarn comprising advancing a continuous multi-filament thermoplastic on a substantially straight line path lirst through a forced hot air oven and then through a iluid twisting nozzle adapted to twist yarn passing therethrough by whirling the fluid about the yarn path through said nozzle in a vacant twisting chamber and in contact with the yarn and by moving the duid in a direction counter to the direction of yarn advance through the nozzle, ballooning the yarn in the oven, and heat-softening the yarn in the oven while the yarn is in a twisted condition imposed upon the yarn by the fluid twisting nozzle located downstream therefrom, and subsequently cooling the yarn While still in said twisted condition to set the twisteinduced crimp into said yarn.

9. A method in accordance with claim 8 in which the operative fluid in said twisting nozzle is at a temperature substantially below the heat-setting temperature of the yarn being textured.

10. In an apparatus for texturing yarn with a fluid twisting nozzle and a circulating hot air oven, the improvement which comprises a plurality of elongated ovens disposed in side-by-side relation with hot air chambers intermediate adjacent ovens, said ovens being adapted to have yarn passed therethrough to be heat treated, the lateral sides of said intermediate hot air chambers form,- ing sides of said ovens, means at the back of said hot air chambers for introducing air into said chambers, means for maintaining a pressure of from 0.20" to 0.65 of water in said intermediate hot air chambers, said lateral sides of said hot air chambers having perforations from %4" to 1A in diameter therethrough with from 5% to 20% of the area of said member being open for introducing air into said ovens, means at the back of said ovens for withdrawing air from said ovens, said withdrawing means being spaced a substantial distance counter to the direction of travel of yarn through the ovens from said introducing means, and means for re-circulating and re-heating said air.

11. Apparatus in accordance with claim 10 in which means are provided for introducing hot air into said chambers at the back thereof near the top thereof and in which the sides of said chambers have openings therethrough from 1/64, to 1A in diameter with from 5 to 20% of ltion substantially tangentially of the outer Wall defining said chamber, passing the fluid from said chamber through the base of and into a conical chamber forming an extension of said annular cross-section chamber adjacent said annular chamber and proportioned and arranged as to have its base coincident with and of the same diameter as one endof the outer wall defining said annular chamber and its axis coincident with an extension of the axis of said annular chamber, passing the yarn to be twisted axially through said conical chamber in a direction from the tip toward the base of the cone, twisting the yarn on its own axis by means of said fluid stream, and removing the yarn from the uid stream through an axial outlet adjacent that end of the annular chamber which is closer to said conical chamber.

14. A method in accordance with claim 13 in which the annular chamber into which the fluid stream is introduced is defined by a cylindrical outer wall, and in which the yarn is removed from the fluid stream through an outlet in the plane defined by the base of the cone.

15. A method in accordance with claim 13 in which the fluid is a gas and including the step of passing the gas stream through succeeding annular cross sections of increasing area in said annular cross section chamber.

16. A method in accordance with claim 15 in which after said gas stream leaves said annular chamber and before it passes into said conical chamber the said gas stream is passed through a cylindrical chamber open to and coaxial with both said annular and said conical chambers and of the same diameter as the base of sai-d conical chamber.

17. A method in accordance with claim 13 in which after said fluid stream leaves said annular chamber and before it passes into said conical chamber the said rluid stream is passed through a `cylindrical chamber open to and coaxial with both said annular and said conical chambers and of the same diameter as the base of said conical chamber.

18. `A twister in accordance with claim 1 in which said nipple is a truncated cone, the tip of said cone pointing toward said conically shaped part of said chamber, and in which said nipple extends substantially completely through said cylindrical shaped part of said chamber.

References Cited by the Examiner UNITED STATES PATENTS 1,616,015 2/27 Wenzel 57-51.5 2,477,909 8/ 49 Stockly 57-34 2,515,299 7/50` Foster et al. 57-77.3 2,734,228 2/56 Hay 28--72 2,779,105 1/57 Park 34--155 2,790,298 4/57 Kunzle 57-34 2,815,559 12/57 Robinson 57-34 2,891,376 6/59 Stoddard et al. 57-157 2,893,198 7/59 Schrenk et al. 57-77.3 '2,951,330 9/60 Bouvet 57-34 2,990,670 7/ 61 Kingsbury 57-34 2,991,614 7/61 Ubbelohde 57-34 3,009,312 11/61 Seem et al. 57-157 3,012,335 12/61 Allandar et al. 34-155 FOREIGN PATENTS 565,364 3/58 Belgium. 773,816 5/57 Great Britain. 825,245 12/ 59 Great Britain.

MERVIN STEIN, Primary Examiner.

UNITED STATES `PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,204,396 September 7, 1965 Boutwell H. Foster et al.

It :Ls hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, line 69, after "thermoplastic" insert yarn Signed and sealed this 6th day of December 1966.

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer Commissioner of Patents EDWARD VI. BRENNERn 

4. APPARATUS FOR TEXTURING THEREMOPLASTIC YARN COMPRISING A FORCED HOT AIR OVEN TO SOFTEN SAID YARN WHILE SAID YARN IS TWISTED, A FLUID TWISTING NOZZLE ADAPTED TO TWIST YARN PASSING THERETHROUGH, SAID FLUID TWISTING NOZZLE INCLUDING WALLS DEFINING A VACANT TWISTING CHAMBER, MEANS FOR WHIRLING SAID FLUID IN CONTACT WITH THE YARN AND ABOUT THE AXIS OF SAID CHAMBER AND TO MOVE THE FLUID AXIALLY INTO AND THROUGH SAID CHAMBER IN A DIRECTION COUNTER TO THE DIRECTION OF YARN ADVANCED THERETHROUGH AND MEANS FOR PASSING THERMOPLASTIC YARN TO BE TEXTURED ON A SUBSTANTIALLY STRAIGHT LINE PATH FIRST THROUGH SAID FORCED HOT AIR OVEN AND THEN THROUGH SAID TWISTING NOZZLE, SAID FLUID TWISTING NOZZLE AND MEANS FOR PASSING YARN BEING CONSTRUCTED AND ARRANGED TO BALLOON THE YARN IN THE CIRCULATING HOT AIR OVEN. 